Alexander Ziegler; Dorothy J. Barr (8 May 2018). "The Historical and Biographical Context of Gregory's Diverticulum, an Unusual Organ in Sand Dollars". Breviora (بالإنجليزية). 559 (1): 1–18. DOI:10.3099/MCZ47.1. ISSN:0006-9698. QID:Q97118157.
Alexander Ziegler; Dorothy J. Barr (8 May 2018). "The Historical and Biographical Context of Gregory's Diverticulum, an Unusual Organ in Sand Dollars". Breviora (بالإنجليزية). 559 (1): 1–18. DOI:10.3099/MCZ47.1. ISSN:0006-9698. QID:Q97118157.
Alexander Ziegler; Dorothy J. Barr (8 May 2018). "The Historical and Biographical Context of Gregory's Diverticulum, an Unusual Organ in Sand Dollars". Breviora (بالإنجليزية). 559 (1): 1–18. DOI:10.3099/MCZ47.1. ISSN:0006-9698. QID:Q97118157.